Intermittent fasting for weight loss: Does it work?

In recent years, intermittent fasting for weight loss has gained traction as a flexible and sustainable approach to managing weight. From wellness influencers to clinical researchers, many are exploring how this eating pattern can support long-term health goals. But what is intermittent fasting, and is it truly effective for weight loss?

Here’s everything you need to know about intermittent fasting for weight loss and a few practical tips to help you decide if intermittent fasting is right for you.

What is intermittent fasting?

Intermittent fasting (sometimes known as IF) is not a diet in the traditional sense. It’s an eating pattern that cycles between periods of eating and fasting. Rather than focusing on what you eat, intermittent fasting focuses on when you eat. The goal is to give your body time to burn through stored energy, which may support weight loss and other health benefits.

During fasting periods, you typically consume only water, tea, coffee or other calorie-free beverages. The idea is that you eat or drink fewer calories if there is less time to have them, so the eating windows allow you to consume your daily calories within a specified timeframe. It’s important to note that while intermittent fasting focuses on timing, pairing it with healthy food choices is key to achieving sustainable results.

Benefits of intermittent fasting

Some potential intermittent fasting benefits go beyond weight loss. Intermittent fasting may support:

• Brain health, including improved cognitive function and memory.
• Heart health, including improving blood pressure and resting heart rates.
• Improved insulin sensitivity, which can enhance fat burning and make stored body fat more accessible for energy.
• Increased longevity and protection against certain health conditions
• Reduced inflammation

Best intermittent fasting methods for weight loss

Choosing the best intermittent fasting for weight loss depends on your lifestyle, health goals and personal preferences. Two of the most widely practiced methods are:

16/8 Method

The 16/8 intermittent fasting method involves fasting for 16 hours and eating during an 8-hour window each day, though you are still allowed to drink water and other zero-calorie beverages. A common schedule is to eat between noon and 8 p.m., which allows you to skip breakfast and still enjoy lunch and dinner.

Why it works for weight loss:

• By shortening your eating window, you may naturally consume fewer calories— leading to weight loss.
• It’s easy to integrate into a busy lifestyle, especially for those who prefer fewer meals or don’t feel hungry for breakfast in the morning.
• Research has shown that time-restricted eating patterns are a promising intervention for weight and metabolic health, particularly for overweight or obese adults.

This method is often considered one of the best intermittent fasting methods for weight loss due to its simplicity and adaptability.

5:2 Diet

The 5:2 intermittent fasting diet involves eating normally five days a week and significantly reducing your calorie intake on two nonconsecutive days, typically to around 500 to 600 calories.

Why it works for weight loss:

• It allows for more flexibility, allowing you to decide which days you fast and what foods you eat.
• It creates a calorie deficit without requiring daily restriction.
• Research has shown the 5:2 diet is just as effective as daily calorie restriction for weight loss and blood sugar control.

The 5:2 diet is ideal for those who prefer not to fast daily but still want to experience the intermittent fasting benefits associated with reduced calorie intake and improved metabolic health.

Side effects of intermittent fasting

Intermittent fasting can have unpleasant side effects. These could include:

• Dehydration
• Digestive issues, such as indigestion, nausea, bloating or diarrhea.
• Fatigue and low energy
• Headaches and feeling lightheaded
• Hunger and cravings
• Mood changes due to fluctuation in blood sugar levels
• Nausea
• Risk of overeating during eating windows

Most side effects go away within a month. But easing into an intermittent fasting plan can help your body adjust and potentially minimize side effects. Some people may also experience a tendency to overeat or binge during eating windows, which can undermine your goals for weight loss and even lead to further digestive discomfort.

Is intermittent fasting a sustainable approach to weight loss?

Sustainability is essential for long-term weight management. For many, intermittent fasting is easier to maintain than traditional diets. Others may find the timing too restrictive. Ultimately, the success of intermittent fasting depends on your personal preferences, lifestyle and health needs. It’s important to choose an approach that feels realistic and supports your overall well-being.

Tips to get started  

If you’re curious about trying intermittent fasting for weight loss, the good news is that getting started doesn’t have to be overwhelming. Whether you're drawn to the structure of the 16/8 method or the flexibility of the 5:2 diet, the key is to find an approach that fits your lifestyle and supports your health goals. Here are some tips to help you ease into intermittent fasting:

1. Talk to your primary care provider

Always talk to your primary care provider before starting any new diet. They can help determine if this is the right approach for you.

2. Choose the right method for you

Select a fasting method that aligns with your lifestyle, work schedule and goals. If you're not a breakfast person, the 16/8 method might feel natural. If you prefer more flexibility throughout the week, the 5:2 approach could be a better fit. The best intermittent fasting for weight loss is the one you can stick with consistently and comfortably.

3. Start gradually

Ease into fasting by shortening your eating window over time or starting with one fasting day per week. This helps your body adapt and reduces the risk of any significant side effects. Starting slowly can also help prevent overeating during eating windows and give your body time to adjust to this new approach.

4. Focus on nutrient-dense foods

It’s not just about when you eat, what you eat matters too. During eating windows, be sure to fill your plate with nutrient-dense foods. Focus on lean proteins, healthy fats, whole grains, fruits and vegetables. Try to avoid processed foods, sugary sweets and consuming too many calories during your eating window.

5. Stay hydrated

Drink plenty of water throughout the day. Zero-calorie beverages like herbal tea or black coffee can help curb hunger during fasting hours.

6. Listen to your body

Pay attention to how you feel and be willing to adjust your approach if needed. If intermittent fasting leaves you feeling unwell or overly restricted, it may not be the right fit—and that’s okay.

Is intermittent fasting right for you?

Intermittent fasting for weight loss can be a promising alternative to traditional dieting. However, it’s not a one-size-fits-all solution. It’s one of many tools available for weight management, and its success depends on how well it aligns with your habits and preferences. Before starting any new diet, consult with your healthcare provider—especially if you have underlying health conditions or specific dietary needs.

For more nutrition advice, connect with a registered dietitian to create a plan to help achieve your health and wellness goals or discover our Healthy Weight program.